The Mishnah on Shabbat teaches us about a prohibition that Chazal (the Sages) made against taking medicine on Shabbat. In the next few days, we’ll learn who that applies to and who it doesn’t apply to. Simply speaking, medicine is asur (prohibited) on Shabbat. What is the reason? One of the melachot (prohibited labors) on Shabbat is called tochen, to grind. Tochen is one of the 39 melachot: to grind. Taking and grinding it is one of the melachot from the Torah. Medicines usually involve different types of herbs or foods, which they grind to make the medicine. The rabbis were concerned that a person who needs medicine on Shabbat, in his rush for a remedy, might go ahead. Therefore, medicine is a gezeira (rabbinic decree), off limits in case someone might come to grind.
Even today, some people among the Poskim (halachic authorities) discuss whether it might no longer be relevant, because today we buy medicine, so nobody makes his own medicine. Number one, we have a rule that any gezeira our rabbis made still exists, even though the reason may no longer be around. That’s number one. And number two, it’s not so clear anyway. First of all, medicine is made the same way it used to be. True, people may not make it at home as much. That’s how it’s made. Plus, people do make it. Some people have home remedies in their homes; they make them. Therefore, it’s not even clear, really, that the reason for the gezeira doesn’t exist. But even if that were so, the status of the gezeira is unclear. So it doesn’t apply today.
Now, this halacha (Jewish law) of medicine does not apply to food eaten by healthy people. That means if a person, for example, wants to have a cup of hot tea to make himself feel better, that’s a refuah (medicine). He’s doing something for the purpose of medicine. However, since the food he’s eating is something that normal, healthy people eat, even if your intention is for medicine, it’s mutar (permitted). Again, it’s not so much that we care about whether you’re taking it for medicine. It’s the item itself: medicine that healthy people generally don’t eat. You’re eating it; that’s the gezeira. Healthy people eat it; that’s called ma’achal beriyim (food of healthy people). One is allowed to consume it on Shabbat, even if he’s doing it for the purpose of feeling better.
There’s an additional part to this gezeira. The rabbis were not only gozer (decreed) on medicine itself; they were also gozer on actions that could also be done through medicine. What’s an example of that? The Shulchan Aruch, in Siman Shin Kaf Chet, says that one is not allowed to exercise, right? It’s in order to sweat. That was a form of refuah: a person would sweat to feel better. Here, the one who exercises is not going to come to grind on Shabbat. It’s totally not connected. So why is there a gezeira? Why is this included in the gezeira? The reason is that there are two ways to sweat. One way to sweat is to take certain medicine that makes sweat come out of the body, even without moving. Or you could exercise. A person isn’t taking the medicine, but since what he’s doing can be done through medicine, that’s included in the gezeira of refuah. So, again, not only is medicine not allowed; even things done without medicine that can be done with medicine are also included in the gezeira.
If you do something for refuah that can’t be done with medicine—for example, a person who puts a brace on Shabbat, he braces on his teeth, right? Well, I’ll put it on—that’s something that cannot be done with medicine. Something like that would be mutar on Shabbat because there is no other alternative that would lead to grinding. Those are basically the basic rules of medicine on Shabbat. Anything that is not considered food for healthy people is considered medicine. Anything that is not considered medicine—anything that people eat—is allowed. Any action that is a replacement for medicine or can be done through medicine is also asur on Shabbat.